This study identified early behavioral, physical and familial characteristics of children with average IQ scores and below average school achievement, approximately 3% of the NCPP population among both whites and blacks. Low achievers, followed from the prenatal period to age 7, were compared with their IQ-matched academically successful controls on prospectively ascertained indices of cognitive and physical development and family environment. Cognitive deficits and behavioral problems in the preschool period were associated with low achievement at age 7. Socioeconomic status (SES) and family structure were better predictors of low achievement than were indices of physical development or medical status. Low achievers were born into low SES, large families, and two-thirds of them were boys. As preschoolers, they had difficulties with verbal tasks and low IQ scores as compared with controls. At age 7, signs of deviant behavior, verbal and non-verbal cognitive deficits, and neurological soft signs were present. Hyperactive low achievers had an increase frequency of obstetrical complications. Sex differences were found in precursors as well as in the incidence of unexpected academic failure. The study is completed and a monograph is in preparation.